[U-Boot] [PATCH v2 2/2] RISCV: image: Parse Image.gz support in booti.

[Marek Vasut <marek.vasut@gmail.com>]

On 5/1/19 12:06 AM, Atish Patra wrote:
> On 4/30/19 2:42 PM, Marek Vasut wrote:
>> On 4/30/19 10:38 PM, Atish Patra wrote:
>>> On 4/30/19 12:11 PM, Marek Vasut wrote:
>>>> On 4/30/19 8:13 PM, Atish Patra wrote:
>>>>> On 4/30/19 2:52 AM, Marek Vasut wrote:
>>>>>> On 4/30/19 3:27 AM, Atish Patra wrote:
>>>>>>
>>>>>> [...]
>>>>>>
>>>>>>>>> Yes. FIT image parsing can be done in that way. However, the idea
>>>>>>>>> was
>>>>>>>>> here to load Image.gz directly. Image.gz is default compressed
>>>>>>>>> Linux
>>>>>>>>> kernel image format in RISC-V.
>>>>>>>>
>>>>>>>> Sigh, and the image header is compressed as well, so there's no
>>>>>>>> way to
>>>>>>>> identify the image format, right ? And there's no decompressor, so
>>>>>>>> the
>>>>>>>> dcompressing has to be done by bootloader, which would need some
>>>>>>>> sort of
>>>>>>>> very smart way of figuring out which exact compression method is
>>>>>>>> used ?
>>>>>>>>
>>>>>>> Yes. Image.gz is always gunzip. So checking first two bytes is
>>>>>>> enough to
>>>>>>> confirm that it is a gz file.
>>>>>>
>>>>>> What happens once people start feeding it more exotic compression
>>>>>> methods, like LZ4 or LZO or LZMA for example ?
>>>>>>
>>>>>
>>>>> booti command help will clearly state that it can only boot kernel
>>>>> from
>>>>> Image or Image.gz.
>>>>>
>>>>> static char booti_help_text[] =
>>>>>        "[addr [initrd[:size]] [fdt]]\n"
>>>>> -    "    - boot arm64 Linux Image stored in memory\n"
>>>>> +    "    - boot arm64 Linux Image or riscv Linux Image/Image.gz
>>>>> stored
>>>>> in memory\n"
>>>>
>>>> Obvious question -- does this Image.gz stuff apply to arm64 ?
>>>>
>>>
>>> arm64 builds Image.gz but booti for arm64 doesn't use it. I guess
>>> Image.gz can be used in FIT image for ARM64 but I am not sure which
>>> platform actually uses it.
>>>
>>> This patch only enables support for RISC-V.
>>
>> Can't this be made generic ?
>>
> 
> I think so if I just move the gzip detection and decompression code to
> cmd/booti.c.
> 
> I will update the v3 patch with this.

Nice, thanks.

But since you're basically implementing file(1)-lite, I wonder whether
there isn't similar code somewhere in u-boot already.

-- 
Best regards,
Marek Vasut